When making homopolymers and copolymers of vinyl and vinylidene halides, and other polymerizable olefinic monomers, by means of the aqueous suspension polymerization technique, these polymerizations are generally exothermic and display a steadily increasing heat load. Frequently, this heat load becomes so severe late in the polymerization that the isothermal control is lost and the reaction "tailpeaks", or its temperature rises significantly above its set point. This tailpeak limits the amount of initiator and monomer, or monomers, which can be charged to the reactor, and therefore, limits the productivity of the reactor.
A number of methods have been heretofore proposed to overcome the difficulty of tailpeaks in vinyl monomer polymerization reactions. In the past, it has been proposed to polymerize at one temperature for a certain period of time and then change the temperature. While such a procedure has beneficial effects, it does not entirely solve the problem. Elaborate computer techniques have also been proposed but this type of equipment is expensive and difficult to install in a plant. Further, various compounds have been proposed to employ in the polymerization recipe which are, in effect, polymerization inhibitors under conventional conditions of temperature and pressure. Compounds of this nature, for this purpose, have been disclosed in U.S. Pat. No. 3,642,756. These materials work very well but it is felt that other materials or compounds, available commercially, might likewise accomplish the same result but in more efficient manner. Accordingly, it is a primary object of the present invention to provide a process for substantially eliminating the tailpeak during the preparation of homopolymers and copolymers of vinyl and vinylidene halides, and other polymerizable olefinic monomers by means of the aqueous suspension polymerization technique.